Farrowing crates prevent sows from performing natural mothering behaviours. Alternative farrowing systems represent a major welfare advance for sows and piglets.
Farrowing crates are designed to prevent piglet crushing but impose severe behavioural restrictions on sows. The motivation to build nests before parturition is one of the strongest drives in pigs, and its frustration causes intense distress measurable through cortisol and stereotypic rooting on crate bars. Swinging crate systems and pen farrowing with creep areas can achieve comparable piglet survival while restoring sow welfare substantially.